Even a science is not merely a ‘body of facts’. It is, at the very least, a collection, and as such it is dependent upon the collector’s interests, upon a point of view. In science, this point of view is usually determined by a scientific theory; that is to say, we select from the infinite variety of facts, and from the infinite variety of aspects of facts, those facts and those aspects which are interesting because they are connected with some more or less preconceived scientific theory. [ch. 25, 535-6]